This invention relates to electronic scale apparatus and more particularly to an electronic scale employing an analog strain gauge and a force collector lever system which is highly stable and acts to concentrate the force collected to a point.
While analog strain gauges are highly sensitive, their use as a force measuring transducer within electronic scales has frequently resulted in devices which were neither highly accurate, precise, nor stable. Thus, electronic scales employing analog strain gauges would typically manifest marked disparities in readings associated with a user improperly positioning or disposing his weight on the scale. Substantial disparities in readings would also occur as a result of a user's position on the device being off center. This resulted in a prevalent conception among the public at large that such electronic scale apparatus was inaccurate and often unreliable when, in fact, the source of such inaccuracies resided in the user's failure to appreciate the critical function which position played in the proper operation of the device.
For instance, in conventional electronic scale apparatus a lever system is utilized to collect the force imposed by a user on the cover of the scale. Such lever systems have not been heretofore designed to focus or concentrate the force collected at a sharply defined location such as a point where such concentrated force could be accurately measured by an analog transducer such as a strain gauge. This failure of the force collecting system to concentrate the force collected at a precise and sharply defined location would result in scale apparatus yielding widely varying results depending upon the position of the user on the device since the transducer would effectively be responding to force distributed over a measurement area. This distribution would vary substantially in accordance with the user's position on the scale.
In addition, while previously available electronic scale apparatus was configured with lever-type force collection systems intermediate a cover and base with the cover being anchored to the base to avoid removal thereof; the cover typically was not anchored in a manner to prevent small displacements thereof with respect to the base. Thus, if a user located himself off-center on the cover the fore/aft or left/right displacement of the force would cause a small rotation in the position of the cover to occur and prevent the force collecting lever system from accurately resolving the resulting force imposed by the user at the collection site. Accordingly, since the force collection schemes employed did not precisely concentrate the force collected at a well-defined site and the collection scheme was subject to error associated with the position of a user, conventional electronic scale apparatus frequently provided results which were inaccurate despite the use of analog strain transducers which, per se, are very sensitive and in themselves highly accurate.
Therefore, it is a principal object of the present invention to provide electronic scale apparatus wherein a lever system is employed to concentrate force at a point and the lever system is disposed to collect the force imposed by a user from a platform which is highly stable and relatively insensitive to a user's position. Various other objects and advantages of the present invention will become clear from the following detailed description of an exemplary embodiment thereof and the novel features will be particularly pointed out in conjunction with the claims appended hereto.